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<h2><a name="SECTION0032140000000000000000"></a><a name="AST_Errors"></a>
<br>
30.1.4 Exceptions and Error Handling 
</h2>

<p>
The parser module defines a single exception, but may also pass other
built-in exceptions from other portions of the Python runtime
environment.  See each function for information about the exceptions
it can raise.

<p>
<dl><dt><b><span class="typelabel">exception</span>&nbsp;<tt id='l2h-5419' xml:id='l2h-5419' class="exception">ParserError</tt></b></dt>
<dd>
Exception raised when a failure occurs within the parser module.  This
is generally produced for validation failures rather than the built in
<tt class="exception">SyntaxError</tt> thrown during normal parsing.
The exception argument is either a string describing the reason of the
failure or a tuple containing a sequence causing the failure from a parse
tree passed to <tt class="function">sequence2ast()</tt> and an explanatory string.  Calls to
<tt class="function">sequence2ast()</tt> need to be able to handle either type of exception,
while calls to other functions in the module will only need to be
aware of the simple string values.
</dd></dl>

<p>
Note that the functions <tt class="function">compileast()</tt>, <tt class="function">expr()</tt>, and
<tt class="function">suite()</tt> may throw exceptions which are normally thrown by the
parsing and compilation process.  These include the built in
exceptions <tt class="exception">MemoryError</tt>, <tt class="exception">OverflowError</tt>,
<tt class="exception">SyntaxError</tt>, and <tt class="exception">SystemError</tt>.  In these cases, these
exceptions carry all the meaning normally associated with them.  Refer
to the descriptions of each function for detailed information.

<p>

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<span class="release-info">Release 2.5.1, documentation updated on 18th April, 2007.</span>
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